Use dogpile.cache to cache the default_buildroot_groups result

module_build_service/utils.py

@@ -1375,3 +1375,31 @@ def get_rpm_release_from_mmd(mmd):
     dist_str = '.'.join([mmd.name, mmd.stream, str(mmd.version)])
     dist_hash = hashlib.sha1(dist_str).hexdigest()[:8]
     return conf.default_dist_tag_prefix + dist_hash
+
+def create_dogpile_key_generator_func(skip_first_n_args=0):
+    """
+    Creates dogpile key_generator function with additional features:
+
+    - when models.ModuleBuild is an argument of method cached by dogpile-cache,
+      the ModuleBuild.id is used as a key. Therefore it is possible to cache
+      data per particular module build, while normally, it would be per
+      ModuleBuild.__str__() output, which contains also batch and other data
+      which changes during the build of a module.
+    - it is able to skip first N arguments of a cached method. This is useful
+      when the db.session or PDCClient instance is part of cached method call,
+      and the caching should work no matter what session instance is passed
+      to cached method argument.
+    """
+    def key_generator(namespace, fn):
+        fname = fn.__name__
+        def generate_key(*arg, **kwarg):
+            key_template = fname + "_"
+            for s in arg[skip_first_n_args:]:
+                if type(s) == models.ModuleBuild:
+                    key_template += str(s.id)
+                else:
+                    key_template += str(s) + "_"
+            return key_template
+
+        return generate_key
+    return key_generator